[j-nsp] Best practice for igp/bgp metrics

[Mark Tinka]

On 25/Oct/17 21:41, Luis Balbinot wrote:

> Never underestimate your reference-bandwidth!
>
> We recently set all our routers to 1000g (1 Tbps) and it was not a
> trivial task. And now I feel like I'm going to regret that in a couple
> years. Even if you work with smaller circuits, having larger numbers
> will give you more range to play around.

IS-IS has no reference-bandwidth concept, but as with you, we've also
used a 1Tbps base, considering multipliers based on whether links are
national or international as well (you don't want local traffic
switching between two different countries that have a very low latency
between one another).

The challenge I had with a 1Tbps base was when links were very small
(for IS-IS, you can easily exceed the actual metric value). But with the
smallest backbone links now sitting at about 10Gbps, it's not a major drama.

Mark.